Due to the continuous demand for smaller microelectronic devices, there exists a need to reduce the size of structural shapes in microelectronics and other related industries. Toward this end, effective lithographic techniques are essential to achieve a reduction in the size of microelectronic structures.
Typical lithographic processes involve pattern-wise exposure of a photosensitive resist to radiation in order to form a patterned resist layer. Thereafter, the resulting image may be developed by contacting the exposed resist layer with a suitable developing substance (e.g. an aqueous alkaline developing solution) to remove certain portions of the resist pattern. The material underlying the resist may then be etched through the openings in the resist to transfer a pattern to an underlying substrate. After the pattern is transferred, the remaining portions of the resist may then be removed.
For better resolution in lithography, an antireflective coating (ARC) may be used to minimize the reflectivity between an imaging layer, such as a photosensitive resist, and an underlying layer. However, in some lithographic imaging processes, the resist does not provide sufficient etch resistance to effectively transfer the desired pattern to a layer underlying the resist. Therefore, a so-called hardmask layer may be applied as an intermediate layer between the patterned resist layer and the underlying material to be patterned. The hardmask layer receives the pattern from the patterned resist layer and should be able to withstand the etching processes needed to transfer the pattern to the underlying material.
Although a number of hardmask materials are known, there is a need for improved hardmask compositions. Since conventional hardmask materials are often difficult to apply to substrates, the use of chemical and physical vapor deposition, special solvents, and/or high-temperature baking may be required. A hardmask composition that may be applied by spin-coating techniques, and which does not require high-temperature baking, would be desirable. A hardmask composition that can be easily etched selective to the overlying photoresist, while being resistant to the etch process needed to pattern the underlying layer, would also be desirable. A hardmask composition that provides superior storage properties and avoids unwanted interactions with an imaging resist layer would further be desirable. A hardmask composition that is particularly resistant to radiation at shorter wavelengths, such as 157, 193, and 247 nm, would also be desirable.